The House of Lords of the United Kingdom, in addition to having a legislative function, historically also had a judicial function. It functioned as a court of first instance for the trials of peers, for impeachment cases, and as a court of last resort within the United Kingdom. In the latter case the House's jurisdiction was essentially limited to the hearing of appeals from the lower courts. Appeals were technically not to the House of Lords, but rather to the Queen-in-Parliament. By constitutional convention, only those lords who were legally qualified (Lords of Appeal in Ordinary, or Law Lords) heard the appeals, since World War II usually in what was known as the Appellate Committee of the House of Lords[1][2] rather than in the chamber of the House.

During the 20th and early 21st centuries, the judicial functions were gradually removed. The final trial of a peer in the House of Lords was in 1935, and in 1948, the use of special courts for trials of peers was abolished. In 2009 the Supreme Court of the United Kingdom assumed the functions as the new court of final appeal in the UK.

Parliament's role in deciding litigation originated from the similar role of the Royal Court, where the King dispensed justice. Parliament grew out of the Court and took on many of its roles. As lower courts were established, the House of Lords came to be the court of last resort in criminal and civil cases, except that in Scotland, the High Court of Justiciary remained the highest court in criminal matters.

Parliament originally did not hear appeals as a court might; rather, it heard petitions for the judgments of lower courts to be reversed. The House of Commons ceased considering such petitions in 1399, leaving the House of Lords, effectively, as the nation's court of last resort. The Lords' jurisdiction later began to decline; only five cases were heard between 1514 and 1589, and no cases between 1589 and 1621. In 1621, the House of Lords resumed its judicial role when King James I sent the petition of Edward Ewer, a persistent litigant, to be considered by the House of Lords. Petitions for the House of Lords to review the decisions of lower courts began to increase once again. After Ewer, 13 further cases would be heard in 1621. The House of Lords appointed a Committee for Petitions. At first, the Clerk of the Parliaments would bring petitions to the House, and the whole House could decide if they should or should not be referred to the Committee. As the number of petitions increased, the Committee gained the power to reject petitions itself.

Petitions to the House of Lords did not have to seek reversal of lower court judgments; often, petitions were brought directly to the Lords without prior consideration in the inferior judiciary. The practice of bringing cases directly to the Lords, however, ended with the case of Thomas Skinner v. East India Company. Thomas Skinner had established a trading base in Asia while there were few restrictions on trade there; later, however, the base was seized by the British East India Company, which had been granted a monopoly. In 1667, the King, Charles II, referred the case to the Lords after failed attempts at arbitration.

Replying to Skinner's petition, the East India Company objected that the case was one of first instance, and that the Lords therefore should not have accepted it. Notwithstanding the Company's protests, the House of Lords proceeded with the matter. Though lawyers argued that the House could intervene only after the lower courts had failed to remedy the case, the Lords decided in Skinner's favour in 1668. The East India Company then petitioned the House of Commons, arguing that the acceptance of a case in the first instance by the Lords was "unusual" and "extraordinary."

A famous dispute then broke out between the two Houses; the Commons ordered the imprisonment of Thomas Skinner and the Lords retaliated by ordering the imprisonment of the Company Chairman. In 1670, Charles II requested both Houses to abandon the case. When they refused, he ordered that all references to the case be expunged from the Journals of both Houses and that neither body continue with the dispute. The House of Lords then ceased to hear petitions in the first instance, considering them only after the lower courts had failed to remedy them.

Even after Skinner's Case was resolved, the House of Lords and House of Commons clashed over jurisdiction in 1675. The House of Commons felt that the upper House had breached its privileges by considering cases in which members of the House of Commons were defendants. After the Lords considered Shirley v. Fagg (Sir John Fagg was a member of the Commons), the Commons warned the Lords to "have regard for their Privileges." Later, the dispute became worse when two more cases involving members of the House of Commons—Thomas Dalmahoy and Arthur Onslow (grandfather of Arthur Onslow the noted Speaker (1728–1761))—came before the House of Lords. One case was from the Court of Chancery, and the other from the equity branch of the Court of the Exchequer. The House of Commons challenged that the Lords could hear only petitions challenging the decisions of common law courts but not those challenging the decisions of courts of equity.

The dispute remained unresolved when Parliament was prorogued in 1675. After the Parliament reassembled in 1677, the cases involving members of the House of Commons were quietly dropped and neither House revisited the dispute.

In 1707, England united with Scotland to form the Kingdom of Great Britain. The question then arose as to whether or not appeals could be taken from Scottish Courts. The Articles provided that "no causes in Scotland be cognoscible by the courts of Chancery, Queen's Bench, Common Pleas or any other court in Westminster Hall; and that the said courts or any other of the like nature after the union shall have no power to cognosce, review or alter the acts or sentences of judicatures in Scotland, or stop the execution of the same." The Articles, however, were silent on appeals to the House of Lords. In 1708, the first Scottish appeal to the Lords arrived, and it was accepted by the House. In 1709, the House ordered that no decree of the lower Scottish courts could be executed while an appeal was pending; that rule was reversed only by the Administration of Justice (Scotland) Act 1808, which provided that the lower Court could determine if the appeal justified the stay of the decree. In 1713, the House of Lords began to consider appeals from Scotland's highest criminal court, the High Court of Justiciary. In 1781, when deciding Bywater v. Lord Advocate, the House recognised that prior to the Union, the High Court of Justiciary had been the court of last resort in Scottish criminal cases. The House agreed not to consider further Scottish criminal appeals.

The Law Lords did not have the power to exercise judicial review over Acts of Parliament. However, in 1972 the UK signed up to be a member of the European Union, and with this accepted European law to be supreme in certain areas so long as Parliament does not explicitly override it (see the ex parteFactortame case). The doctrine of Parliamentary sovereignty still applies – under UK constitutional law, Parliament could have at any time unilaterally decided to dismiss the supremacy of European law. In common with other courts in the European Union, however, the Law Lords referred points involving European Union law to the European Court of Justice. The Lords could also declare a law inconsistent with the European Convention on Human Rights pursuant to section 4 of the Human Rights Act 1998. Whilst this power was shared with the Court of Appeal, the High Court, the High Court of Justiciary, the Court of Session, and the Courts-Martial Appeal Court, such declarations were considered so important that the question would almost inevitably be determined in the House of Lords on appeal. However, the challenged law in question was not automatically struck down; it remained up to Parliament to amend the law.

In criminal cases, the House of Lords could hear appeals from the Court of Appeal of England and Wales, the High Court of England and Wales, the Court of Appeal in Northern Ireland and the Courts-Martial Appeal Court but did not hear appeals from the High Court of Justiciary in Scotland. In addition to obtaining leave to appeal, an appellant also had to obtain a certificate from the lower court stating that a point of general public importance was involved. The effect of this was that, in criminal matters, the House of Lords could not control its own docket.

Permission to appeal could be granted by an Appeal Committee. The Committee consisted of three Lords of Appeal or Lords of Appeal in Ordinary. Appeal Committees could not meet while Parliament was prorogued or dissolved. Formerly, leave to appeal was unnecessary if two solicitors certified the reasonableness of the case. This procedure was abolished in English cases in 1934 and in Northern Irish cases in 1962; Scottish cases continued to come before the House of Lords in a similar manner.

An Appellate Committee, normally consisting of five Lords of Appeal in Ordinary or Lords of Appeal, heard the actual appeals. The minimum number of Law Lords that could form a Committee was four. Seven Lords could sit in particularly important cases. On 4 October 2004 a Committee of nine Lords, including both the Senior Law Lord Lord Bingham of Cornhill and Second Senior Law Lord Lord Nicholls of Birkenhead, was convened to hear challenges to the indefinite detention of suspects under the Anti-terrorism, Crime and Security Act 2001, and on 16 December it announced an 8-1 ruling against the Government.[3] Only five Appellate Committees ever comprised nine members. Three of these occurred after 2001.[citation needed]

The determination of each Appellate Committee was normally final, but the House of Lords (in common with the Court of Appeal and High Court of England and Wales) retained an inherent jurisdiction to reconsider any of its previous decisions, this includes the ability to "vacate" that decision and make a new one. It was exceptional for the House of Lords to exercise this power, but a number of important cases such as Dimes v Grand Junction Canal (a seminal case on bias in England and Wales) proceeded in this way.

Formerly, appeals were heard in the House of Lords Chamber. The Lords would sit for regular sessions after four in the evening, and the judicial sessions were held prior to that time. During the Second World War, the Commons Chamber was bombed, so the Commons began to conduct their debates in the Lords Chamber. The judicial sessions of the House were temporarily moved to a Committee room, which escaped the noise of building repairs. The temporary move later became permanent, and appeals continued to be heard in Committee rooms. No judicial robes were worn by the judges during hearings. Appellate Committees could meet while Parliament was prorogued. Additionally, if the Sovereign authorised the same, the Committee could meet while Parliament was dissolved.

Judgment was given in the main House of Lords Chamber during a full sitting. Sittings for the purposes of giving judgment were normally held at two o'clock on Thursday afternoons; non-judicial matters were not dealt with during these sittings. Only the Law Lords who served on the Appellate Committee spoke, but other Lords were free to attend, although they rarely did so. After all five members of the Committee had spoken, the question was put to the House: "That the report from the Appellate Committee be agreed to." The House then voted on that question and on other questions related thereto; the decisions on these questions constituted the House's formal judgment.

If the House of Lords was in recess, the Lord Chancellor or Senior Lord of Appeal in Ordinary could recall the House to give judgment. Judicial sittings could occur while Parliament was prorogued, and, with the authorisation of the Sovereign, dissolved. In the latter case, the meeting was not of the full House, but was rather of the Law Lords acting in the name of the full House. Judgment could not be given between the summoning of a Parliament and the State Opening. No Parliamentary business is conducted during that time, except the taking of oaths of allegiance and the election of a Speaker by the House of Commons.

The Judicial Committee of the Privy Council, which includes the twelve Lords of Appeal in Ordinary as well as other senior judges in the Privy Council, has little domestic jurisdiction. The Committee hears appeals from the appellate courts of many independent Commonwealth nations and crown dependencies. The Judicial Committee's domestic jurisdiction was very limited, hearing only cases on the competency of the devolved legislatures in Scotland, Northern Ireland, and Wales. Precedents set in devolution cases, but not in other matters, are binding on all other courts, which included the House of Lords. The 'devolution issues' were transferred from the Privy Council to the Supreme Court of the United Kingdom; however, it continues to hear Commonwealth appeals.

Formerly, the House of Lords constituted a court in certain trials, including trials of peers of the realm and impeachment cases. Such trials, however, do not occur any longer; trials for peers of the realm in the House were abolished in 1948,[7] and impeachment has not occurred since 1806.

Peers of the Realm were formerly entitled to a trial in the House of Lords, just as commoners were entitled to trial by jury. Peers of Ireland were, after Union with Great Britain in 1801, entitled to be elected to the House of Commons, but during their service in the lower House their privileges, including the privilege of trial in the House of Lords, abated. Peeresses in their own right and wives or widows of peers were also entitled to trial in such a court, though they were themselves not members of the House of Lords. Widows of peers who later married commoners lost the privilege, but those who later married peers did not.

After the Grand Jury indicted a peer, the case was brought before the Court of King's Bench. The judges of that court could not actually accept any plea of guilty or not guilty, except a plea that the crime in question was previously pardoned. If pardon was not pled, the court issued a writ of certiorari moving the indictment to the House of Lords.[8] The Lord High Steward presided, but the entire House could decide all legal, factual or procedural disputes. At the end, the Lords then voted, starting with the most junior baron, and proceeding in order of precedence, ending with the Lord High Steward. While jurors voted on oath or affirmation, a lord could vote upon his honour. Bishops could not be tried in the House, because they were not peers, but they could participate as judges in a trial, except in the verdict.[9]

If the House of Lords was not in session, the case would be referred to the Lord High Steward's Court. The Lord High Steward, who presided, was the sole judge of questions of law or procedure, but a jury of "Lords Triers" determined the Court's verdict. The Lord High Steward selected, at his discretion, any 23 or more peers to be Lords Triers. A simple majority of votes was enough to convict, but this could not be less than 12.[10] Since the Crown appointed the Lord High Steward, the peers felt that in a political prosecution this procedure put the defense at a severe disadvantage (since the Crown could appoint a hostile Lord High Steward, and he could then select hostile peers as Lords Triers), and in the late seventeenth century made repeated efforts to ameliorate it.

The House of Lords also has the power to try impeachments. The House of Commons decides on "Articles of Impeachment," which are then brought before the House of Lords. Originally, the House of Lords held that it could try peers only upon impeachment. In 1681, however, the Commons passed a resolution arguing that they could impeach any peer or commoner they pleased, and for any crime, whether treason, a felony or a misdemeanour.

The House of Lords may decide the case by a simple majority. When the Commons demand judgment, but not earlier, the Lords may proceed to pronounce the sentence against the accused. It is possible for the House of Commons to refuse to press for judgment, in which case the accused, though convicted, is not subjected to punishment.

The accused may not, under the Act of Settlement 1701, plead a pardon to avoid trial in the House of Lords; the same rule does not apply in the lower courts. A convict, however, may be pardoned by the Sovereign. This practice differs from that of many other nations. For instance, in the United States, the President may not issue pardons in cases of impeachment. The Senate can do no more than remove the accused from office and bar him from future offices of public trust or honour, though the accused remains liable to trial and punishment in the lower courts after removal from office. In the United Kingdom, however, the impeachment trial is like any other trial: the House of Lords may impose the same sentence as any lower court, and the Sovereign may pardon the individual convicted upon impeachment like any other convict.

Impeachment was originally used to try those who were too powerful to come before the ordinary courts. During the reign of the Lancastrians, impeachments were very frequent, but they reduced under the Tudors, when bills of attainder became the preferred method. During the reign of the Stuarts, impeachment was revived; Parliament used it as a tool against the King's ministers during a time when it felt it needed to resist the tyranny of the Crown. The last impeachment trials were the Impeachment of Warren Hastings from 1788 to 1795 and the Impeachment of Viscount Melville in 1806.

Disputes involving peerage claims were normally referred by the Crown to the House of Lords, perhaps because hereditary peers were, prior to the House of Lords Act 1999, members of that House. Theoretically, the Crown, as fount of honour, is entitled to decide all questions relating to peerage disputes. In practice, however, such decisions are made in contentious cases only after a reference is made to the House of Lords.

Under modern procedure, the House of Lords refers the matter to the Committee for Privileges, which until October 2009 included a number of Law Lords. The Law Lords were the ones who give opinions on the case, the other Lords normally concurring therein. However the Law Lords were removed from the House when the Supreme Court came into operation.

The House of Lords then adopts the Committee's report and addresses the Sovereign, requesting the resolution of the case. The Sovereign then determines the issue as decided by the Privileges Committee.

At first, all members of the House of Lords could hear appeals. The role of lay members of the House in judicial sittings began to fade in the nineteenth century. Soon, only "Law Lords"—the Lord Chancellor and Lords who held judicial office—came to hear appeals. The last time that lay members of the House actually voted on a case was in 1834. The Lords later came close to breaching this convention a decade later, when the House was considering the case of Daniel O'Connell, an Irish politician. A panel of Law Lords—the Lord Chancellor, three former Lord Chancellors, a former Lord Chancellor of Ireland and a former Lord Chief Justice—opined on the matter. Immediately thereafter, lay members began to make speeches about the controversial case. The Lord President of the Privy Council then advised that lay members should not intervene after the Law Lords had announced their opinions. The last time a lay peer attempted to intervene was in 1883; in that case, the Lord's vote was ignored.[11]

There was, however, no provision whereby the number of Law Lords could be regulated. In 1856, it was desired to increase the number of Law Lords by creating a life peerage. The House, however, ruled that the recipient of the peerage, Sir James Parke, was not entitled thereby to sit as a Lord of Parliament.

Under the Appellate Jurisdiction Act 1876, the Sovereign nominated a number of Lords of Appeal in Ordinary to sit in the House of Lords. In practice, they were appointed on the advice of the Prime Minister (they were not covered by the Judicial Appointments Commission established in 2006). Only individuals who had held high judicial office for a minimum of two years or barristers who had been practicing for fifteen years were to be appointed Lords of Appeal in Ordinary. By convention, at least two of the Lords of Appeal in Ordinary were Scottish and at least one from Northern Ireland.

Lords of Appeal in Ordinary held the rank of Baron and seats in the House for life. Under the Judicial Pensions and Retirement Act 1993 they ceased to be Lords of Appeal in Ordinary at the age of seventy, but could be permitted by ministerial discretion to hold office as late as age seventy-five. The original Act provided for the appointment of only two Lords of Appeal in Ordinary, but as of 2009 twelve could be appointed; this number could have been further raised by a Statutory Instrument approved by both Houses of Parliament. Lords of Appeal in Ordinary were, by custom, appointed to the Privy Council if not already members. They served on the Judicial Committee of the Privy Council, which is the highest court of appeal in certain cases. Lords of Appeal in Ordinary were often called upon to chair important public inquiries, such as the Hutton inquiry.

Two of the Lords of Appeal in Ordinary were designated the Senior and Second Senior Lords of Appeal in Ordinary. Formerly, the most senior of the Law Lords took these posts. Since 1984, however, the Senior and Second Senior Lords were appointed independently.

Lords of Appeal in Ordinary were joined by a number of Lords of Appeal. The Lords of Appeal were individuals who are already members of the House of Lords under other Acts (including the Life Peerages Act 1958 and the House of Lords Act 1999) who held or had held high judicial office. High judicial officers included judges of the Court of Appeal of England and Wales, the Inner House of the Court of Session and the Court of Appeal in Northern Ireland. Additionally, a Lord of Appeal in Ordinary who had reached the age of seventy could become a Lord of Appeal. Between 1996 and 2001, Lord Cooke of Thorndon, a retired judge of an overseas appellate court (the Court of Appeal of New Zealand), served as a Lord of Appeal.

Judicial appeals were heard by Lords of Appeal in Ordinary and Lords of Appeal under the age of seventy-five. Lords of Appeal in Ordinary were entitled to emoluments. Thus, Lords of Appeal in Ordinary ceased to be paid at the time they ceased to hold office and became Lords of Appeal. The Senior Lord of Appeal in Ordinary received £185,705 as of 2009 (the Lord Chief Justice of England and Wales was the only judicial figure who received a higher salary). The other Lords of Appeal in Ordinary received £179,431.

By convention, only the Lords of Appeal in Ordinary and Lords of Appeal participated in judicial matters. When the House gave judgment, the regular quorum of three applied, but those three had to be Law Lords. Normally, only the Law Lords on the Appellate Committee who were deciding the case voted when the House gave judgment.

The Lord High Steward presided over the House of Lords in trials of peers, and also in impeachment trials when a peer was tried for high treason; otherwise, the Lord High Chancellor presided. The post of Lord High Steward was originally hereditary, held by the Earls of Leicester. After the rebellion of one of the Lord High Stewards, the position was forfeited and re-granted to Edmund Crouchback, but it later merged in the Crown. The position was created again, but its holder died without heirs in 1421, and the post has since been left vacant. Whenever a Lord High Steward became necessary—at certain trials and at coronation—one was appointed for the occasion only. Once the trial or coronation concluded, the Lord High Steward would break his white staff of office, thereby symbolising the end of his service in that position. Often, when a Lord High Steward was necessary for trials of peers, the Lord Chancellor was appointed to the post.

The Lord High Steward merely presided at trials, and the whole House could vote. The position of the Lords Spiritual (the Archbishops and Bishops of the Church of England with seats in the House), however, was unclear. The Lords Spiritual, though members of the House, were not considered "ennobled in blood" like the temporal peers. Though they retained the right to vote in both trials of peers and impeachment trials, it was customary for them to withdraw from the chamber immediately before the House pronounced judgment. This convention was followed only before the final vote on guilt and not on procedural questions arising during the trial.

When the House was not officially in session, trials were heard by the Court of the Lord High Steward.

Disputes over peerage claims are considered before the House of Lords Committee for Privileges. That Committee includes the Chairman of Committees and fourteen other Lords. It remains to be seen what practice the House and the Committee will adopt since the abolition of Law Lords in October 2009.
Before then, the permanent members of the Committee were joined by four Law Lords named by the Senior Lord of Appeal in Ordinary. The Law Lords on the Committee are not permanent members; different Law Lords could sit for different cases. Normally, the Law Lords were the members who opined on the law, the other members merely concurring with their opinions. In hearing peerage claims, at least three Law Lords had to be present in order to maintain a quorum.

In 1873, the Government introduced a bill to abolish the judicial role of the House of Lords in English cases (Scottish and Irish appeals were to be preserved). The bill passed, and was to come into force in November 1874. Before that date, however, the Liberal Government of William Ewart Gladstone fell. The new Conservative Government, led by Benjamin Disraeli, passed a bill to postpone the coming-into-force of the bill until 1875. By then, however, the sentiments of the Parliament had changed. The relevant provisions of the bill were repealed, and the jurisdiction of the House of Lords came to be regulated under the Appellate Jurisdiction Act 1876.

There were concerns related to the role of the House of Lords as a judicial body. The participation of the Lord Chancellor in judicial sittings varied over the years. Lord Gardiner (Lord Chancellor from 1965 to 1970) sat on four days, Lord Hailsham of St Marylebone (1970 to 1974 and 1979 to 1987) on eighty-one days, Lord Elwyn-Jones (1974 to 1979) on eight days, Lord Havers (1987) never, Lord Mackay of Clashfern (1987 to 1997) on sixty days and Lord Irvine of Lairg (1997 to 2003) on eighteen days. Lord Chancellors generally did not sit judicially when the Government had a stake in the outcome; during a debate in the Lords, Lord Irvine said, "I am unwilling to lay down any detailed rules because it is ever a question of judgment combined with a need to ensure that no party to an appeal could reasonably believe or suspect that the Lord Chancellor might, because of his other roles, have an interest in a specific outcome. Examples might be where the lawfulness of a decision or action by any Minister or department might be at issue." The next Lord Chancellor, Lord Falconer of Thoroton, decided not to sit judicially at all. Under the Constitutional Reform Act 2005 the Lord Chancellor is no longer a judge.

Part 3 of the Constitutional Reform Act 2005, which came into force on 1 October 2009, abolished the appellate jurisdiction of the House of Lords, and transferred it to a new body, the Supreme Court of the United Kingdom. Ten of the initial Justices of the Supreme Court were ten of the twelve then existing Lords of Appeal in Ordinary (Law Lords). One of the Law Lords (Lord Scott of Foscote) had retired on 30 September 2009 and the 12th, Lord Neuberger of Abbotsbury, became the Master of the Rolls (the senior judge who heads civil justice in England and Wales). The 11th place on the Supreme Court was filled by Lord Clarke (previously the Master of the Rolls), a member of the House of Lords who was the first Justice to be appointed directly to the Supreme Court. The 12th place was initially vacant. Although the Justices will still be formally addressed in the Supreme Court as "My Lord" or "My Lady", future appointees will not be elevated to the House of Lords.